On my 1999 Passat the push button switch to release the filler cap is on the centre consol, so it should be just about below the driver's right elbow. Not an intuitive location is it? If it is not in the same position as I've described look around for a half inch square button with a bowser symbol. If your interior trim is like mine everything is black and these items are not that obvious. Hope you can find it ok.
Are you sure that the dimmer switch is working?
On my 98 passat I push the button on the end of my wipers lever -
Depends on the model
how do you remove a 1999 vw passat radio
VOLKSWAGEN PASSAT 1998-ON 5x112
The flasher is built into the emergency hazard switch. Just pop out the bottom pieces and its then easier to get your finger in and pop out the flasher.
It is screwed into the bottom passenger side of the radiator. Be careful. When you unscrew the switch to replace it, coolant will pour out. If you are quick you will only lose about a quart.
The Horn on a Passat is operated by pressing the centre of the steering wheel.
My 1999 Passat has 225000 miles and still going strong
If you have a 1999 Passat V6, the coolant temperature sensor is located in the lower radiator hose.
replace your abs module its a common problem with v6 passat 99-2003 model.
http://www.tobio.info/passat/howtos/passat_air_filter.html